Tuning HP Tru64 UNIX V5.1A and V5.1B for Oracle

ManualsBrandsHP ManualsSoftwareTru64 UNIX 5.1B

Environments

Introduction ...................................................................................................................................3

Operating System Versions and Service PAKs......................................................................................4

Prior Version Support...................................................................................................................4

Patches Applicable to Systems Running Oracle.................................................................................4

Tru64 UNIX/TruCluster Server V5.1B-2 with PK4 Service PAK.........................................................4

Tru64 UNIX/TruCluster Server V5.1B-3 with PK5 Service PAK.........................................................4

Tru64 UNIX/TruCluster Server V5.1A with PK6 Service PAK...........................................................4

Location of Patches and Service PAKs.............................................................................................4

Key Tunable Parameters...................................................................................................................5

VM Subsystem............................................................................................................................5

new_wire_method....................................................................................................................5

ubc_maxpercent......................................................................................................................5

ubc_minpercent.......................................................................................................................6

ubc_borrowpercent..................................................................................................................6

vm_ubcseqpercent...................................................................................................................6

vm_ubcseqstartpercent..............................................................................................................6

vm_ubcdirtypercent..................................................................................................................6

vm_swap_eager......................................................................................................................6

ubc_overflow..........................................................................................................................7

vm_overflow...........................................................................................................................7

Shared Memory Allocation and Granularity Hints.............................................................................7

Generic Subsystem......................................................................................................................9

sched_distance........................................................................................................................9

cpus_in_rad............................................................................................................................9

AdvFS Subsystem........................................................................................................................9

AdvfsSyncMmapPages .............................................................................................................9

Obsolete AdvFS system parameters ..........................................................................................10

VFS Subsystem..........................................................................................................................10

fifo_do_adaptive ...................................................................................................................10

smoothsync...........................................................................................................................10

bufcache and bufpages..........................................................................................................11

IPC Subsystem..........................................................................................................................11

ssm_threshold .......................................................................................................................11

Summary of content (19 pages)

PAGE 1
Tuning HP Tru64 UNIX V5.1A and V5.1B for Oracle Environments Introduction ................................................................................................................................... 3 Operating System Versions and Service PAKs...................................................................................... 4 Prior Version Support...................................................................................................................
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shm_max.............................................................................................................................. 11 shm_min .............................................................................................................................. 11 shm_mni .............................................................................................................................. 12 shm_seg............................................................................................
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Introduction This document provides some generic guidelines on how to set key tunable parameters applicable to Oracle® environments running HP Tru64 UNIX V5.1B. In addition, specific patches are recommended for use in Oracle environments. Where appropriate, there are also recommendations for Tru64 UNIX V5.1A; since this release is still supported by HP under a Prior Version Support with Sustaining Engineering (PVS-SE) support agreement. Although Tru64 UNIX V4.0F and V4.
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Operating System Versions and Service PAKs The current supported release of HP Tru64 UNIX and TruCluster Server is V5.1B. This is the last release of Tru64 UNIX and TruCluster Server. HP will continue to support these products until at least 2011. As of March 2006, the supported patch kits for HP Tru64 UNIX V5.1B are V5.1B-2 (PK4) Service PAK and V5.1B-3 (PK5) Service PAK; these are the only supported and recommended Service PAKs to use for Oracle installations running HP Tru64 UNIX V5.1B.
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Key Tunable Parameters This section describes the various kernel parameter changes that HP recommends for use in an Oracle environment. HP recommends that only those parameters that are changed from the default value be included in the /etc/sysconfigtab file. HP further recommends that changes to the /etc/sysconfigtab file are made using the sysconfigdb command. When the version of the release to which a parameter applies is not explicitly mentioned, then the recommendation is valid for both Tru64 UNIX V5.
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The recommended value for ubc_maxpercent should be at least 70%, but less than 100%, and should not be set to a value smaller than 35%. ubc_minpercent The value for this parameter represents the minimum amount of memory available for the UBC. When this parameter is set to a very low value, it may cause severe performance problems on buffered file system operations such as file copies. This is especially true on NUMA systems where the UBC is distributed over the Resource Affinity Domains (RAD)s.
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Setting vm_swap_eager = 0 will cause the system to enter a deferred swap allocation mode. Use lazy swap allocation mode for any system that does not overcommit memory resources. If vm_swap_eager has been set to 0 and the system runs out of allocatable swap space, any process that tries to allocate additional swap space will be terminated by the kernel. There are no mechanisms available to protect processes from being terminated in this situation.
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used by the database for its System Global Area (SGA) or any other application using shmget() or nshmget() to allocate shared memory. Using granularity hints memory offers the best performance and is ideally suited for large GS class AlphaServer systems, especially those with applications that have many processes attached to a large shared memory region (such as large Oracle databases).
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The sum of rad_gh_regions[*] should be set to the size of the Oracle SGA; however, you may consider allocating a larger value for rad_gh_regions in order to be able to resize the Oracle SGA without having to reboot the system; rad_gh_regions is not a dynamic system tunable parameter so any changes will require a system reboot). Setting rad_gh_regions to a larger value than initially required or calculated can provide the benefit of being able to allocate a larger SGA without having to reboot the system.
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Obsolete AdvFS system parameters The following AdvFS tunable parameters are obsolete since the integration of AdvFS with the regular UBC mechanisms in Tru64 UNIX V5.1: • AdvfsCacheMaxPercent • AdvfsCacheHashSize • AdvfsCleanupPercent • AdvfsMaxFreeAccessPercent • AdvfsMinFreeAccess Those parameters are no longer used to tune the AdvFS buffer cache and should be removed from /etc/sysconfigtab. Use the UBC parameters ubc_maxpercent and ubc_minpercent to tune the file system cache.
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smsync:23:wait:/sbin/sysconfig -r vfs smoothsync_age=4 > /dev/null 2>&1 bufcache and bufpages If none of the file systems are UFS based, then some memory can be freed up by setting the following parameters. On systems with less than 2 GB of memory, set vfs:bufcache=1. On systems with more than 2 GB of memory, set vfs:bufpages=2048 and remove any setting of vfs:bufcache from /etc/sysconfigtab. IPC Subsystem Modify the following tunable parameters in the ipc subsystem section of /etc/sysconfigtab.
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shm_mni This tunable parameter specifies the maximum number of shared memory regions that can be used on the system at one time. When NUMA is enabled in Oracle, Oracle will allocate several shared memory segments for each RAD. Oracle will allocate these segments for each instance running on the system. This value should be large enough to cover all instances. This parameter is a limit, which does not have performance implications. The recommended value for shm_mni is 256.
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The default value of the attribute is 5000; therefore, the maximum number of outgoing connections is, by default, 3976 (5000 – 1024). On systems with a large number of connections, this value should be raised. On TruCluster Server configurations that do not use Memory Channel as the cluster interconnect, this value should be raised to 65536. The recommended value for ipport_userreserved on large-scale Oracle installations should be the maximum value of 65535.
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value than actual memory available. However this would allow a single process to outgrow a systems main memory and cause extensive swapping and paging. It is highly recommended to stay within the bounds of the available memory for this tunable parameter, and never raise the tunable parameter to a value larger than the physical memory available plus the configured swap space. The recommended maximum value for per_proc_address_space is 0x40000000000.
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max_async_req HP recommends setting this tunable parameter to at least 256. Note: As of Tru64 UNIX V5.1B-2 (PK4) Service PAK, the default value for this parameter has been raised to 1000. max_sessions HP recommends setting this tunable parameter to at least the number of Oracle processes plus 2. rdg_max_auto_msg_wires HP recommends setting this tunable parameter to 0.
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Although Oracle 8.1.7 Oracle Parallel Server (OPS) does support the use of RDG for communication it is not recommended to enable RDG and to continue to use UDP instead. The following commands show how to enable/disable the different protocols for IPC. To enable Oracle RAC: cd $ORACLE_HOME/rdbms/lib For Oracle 8i: make -f ins_rdbms.mk ops_on make –f ins_rdbms.mk ioracle For Oracle 10g/9i: make -f ins_rdbms.mk rac_on make -f ins_rdbms.
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cd $ORACLE_HOME/rdbms/lib make -f ins_rdbms.mk numa_off make -f ins_rdbms.mk ioracle Note: In the Oracle Database Reference, enabling NUMA options is referred to as “Enabling Oracle Database Directed Placement Optimizations”. Enabling NUMA support in Oracle is currently not supported before Oracle 9iR2 in combination with RAC. If you are planning to use RAC you must have NUMA disabled. Starting with Oracle 9.
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For more information Tru64 UNIX NUMA Overview http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/V51_HTML/NUMA/TITLE.HTM Tru64 UNIX V5.1B Base Operating System Documentation http://h30097.www3.hp.com/docs/pub_page/V51B_DOCS/V51B_DOCLIST.HTM TruCluster V5.1B Documentation http://h30097.www3.hp.com/docs/pub_page/cluster51B_list.html Tru64 UNIX and TruCluster Server best practices documentation http://h30097.www3.hp.
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Acknowledgments Thanks are due to everyone who assisted with the creation of this document, particularly the following: Han Pilmeyer, primary contributor Mario Broodbakker Geoff Gardner Hein van den Heuvel Jan Mark Holzer Bill Kirk Euan McMaster John Shakshober Thomas Sjolshagen Revision Information This is a new document. © 2006 Hewlett-Packard Development Company, L.P. The information contained herein is subject to change without notice.